What is the recommended treatment for a patient with suspected partial tear of the subscapularis tendon and osteoarthrosis of the acromioclavicular joint?

Management of Suspected Subscapularis Partial Tear with AC Joint Osteoarthrosis

Begin with conservative management including relative rest, NSAIDs, and physical therapy for at least 3-6 months before considering surgical intervention, while obtaining MRI to definitively characterize the subscapularis tear and guide treatment decisions. 1, 2

Immediate Diagnostic Step

Obtain MRI of the shoulder without contrast to definitively characterize the subscapularis tendon pathology and distinguish between tendinosis versus partial-thickness tear. 1 The ACR Appropriateness Criteria rates MRI as a 9 (usually appropriate) for evaluating suspected rotator cuff pathology when radiographs are noncontributory 1. MRI has 95% sensitivity and 95% specificity for detecting rotator cuff tears, degeneration, and partial tears 1. This distinction is critical because it determines whether surgical repair is indicated versus continued conservative management.

Conservative Management Protocol (First-Line Treatment)

Activity Modification and Rest

• Implement relative rest by reducing activities that provoke pain during abduction, while maintaining sufficient shoulder movement to prevent muscle atrophy and joint stiffness 1, 2
• Avoid complete immobilization as this causes muscle atrophy and deconditioning 1
• Continue activities that do not worsen pain 1

Pain Management

• Use NSAIDs for acute pain relief, preferring topical formulations to eliminate gastrointestinal bleeding risk associated with systemic NSAIDs 1, 2
• Apply ice therapy through a wet towel for 10-minute periods for short-term pain relief and swelling reduction 1

Physical Therapy

• Initiate eccentric strengthening exercises to stimulate collagen production and guide normal alignment of newly formed collagen fibers 1
• Include stretching exercises as they are widely accepted and thought to be helpful 1
• Tensile loading of the tendon promotes healing through controlled stress 1

Critical Caveat: Avoid Corticosteroid Injections

Do not inject corticosteroids into or around the subscapularis tendon as they may reduce tensile strength, inhibit healing, and predispose to complete tendon rupture 1, 2. While corticosteroid injections may provide short-term pain relief, they do not alter long-term outcomes and have deleterious effects on tendon tissue 1.

AC Joint Osteoarthrosis Management

Conservative Approach

• The AC joint osteoarthrosis can be managed conservatively with oral analgesics or anti-inflammatories and activity modification 3
• Physical therapy has limited benefit for AC joint arthritis as therapeutic exercise plays only a minor role 3
• If diagnostic local anesthetic injection into the AC joint provides relief, consider corticosteroid injection for short-term pain relief 3

Important Distinction

Note that corticosteroid injections are contraindicated for the subscapularis tendon pathology but may be appropriate for the AC joint if diagnostic injection confirms it as a pain source 3. The AC joint injection does not alter disease progression but may provide symptomatic relief 3.

Surgical Indications and Timing

For Subscapularis Tendon

Surgical repair is indicated if:

• Conservative treatment fails after 3-6 months 1, 4
• MRI demonstrates a partial tear greater than 50% of tendon thickness 1
• Full-thickness tear is identified 4, 5

Early surgical repair within 3 weeks may be considered for acute traumatic subscapularis tears 1, though this patient's presentation suggests chronic degenerative pathology rather than acute trauma.

For AC Joint

Surgical distal clavicle excision (open or arthroscopic) is indicated after minimum 6 months of unsuccessful conservative treatment 3, 6. Studies show no significant difference between open versus arthroscopic approaches, with both achieving good outcomes when 0.5-2 cm of clavicle is excised 6.

Follow-Up Timeline

• Pursue conservative management for 3-6 months before reassessing for surgical candidacy 1, 4
• Monitor for progression of symptoms, particularly weakness with internal rotation or pain with abduction 4
• Repeat clinical examination to assess response to conservative measures 1

Key Clinical Pearls

• The patient's pain with abduction on dynamic maneuvers may originate from either the subscapularis pathology or AC joint osteoarthrosis, making the MRI critical for treatment planning 1
• Subscapularis tears in elderly patients or those with partial tears often respond to conservative treatment and may not require surgery 4
• Concomitant shoulder procedures (addressing both subscapularis and AC joint pathology) can be performed simultaneously with good outcomes if surgery becomes necessary 6